Field of Invention
The present invention relates to an antenna; and more particularly to a combined Radar/ESM antenna system and related method.
An electronic support measures (ESM) system involves receiving and analyzing radiated electromagnetic energy transmitted by a remote transmitter for determining the characteristics and source of the energy. For example, a conventional ESM receiver may process received radar pulses to identify the center frequency, amplitude, pulse width, and time of arrival. For some applications, such received electromagnetic energy, together with the relative bearing of the transmitter is merely displayed in the cockpit of the aircraft. In other applications, the received energy is used to control the transmission of electronic countermeasure signals (ECM).
It is desirable for an aircraft not only to have a radar system for detecting threats or targets; but also, to be equipped with ESM for detecting signals emanating from such threats. For aircraft having both such systems, it is necessary that the return energy from the aircrafts own system is distinguished from signals generated by other transmitters. In order to meet this requirement, it is necessary to use a different antenna for each system. This can be accomplished with relative ease in airborne systems mounted on large aircraft. However, in small aircraft that utilize a radome mounted antenna, there is little remaining space in the radome for mounting an additional antenna.